Storage container and system

ABSTRACT

A stackable container has a body with base, pair of opposing side walls and pair of opposing end walls, the walls extending from the base to form an opening having a rim portion extending around its upper periphery. A lid member is pivotally mounted to the body to close the opening and provide access through the opening. One or more connector members are provided with the body and are operable between stored and active states. In the active state, the connector members enables interconnection with an adjacent container so as to support the container in a stacked arrangement, whereby an adjacent container does not prohibit access into the opening of another adjacent container.

BACKGROUND OF INVENTION

The present invention relates to storage bins or containers, and in particular storage bins or containers that are capable of being stacked to provide a readily accessible storage system as well as storage bins or containers that can be stored when not in use without taking up considerable storage space.

Storage bins or containers are commonly used in a variety of situations to store and retain a variety of goods. Such bins or containers have particular application to residential environments where they may be used to store children's toys and other such items in a neat and tidy manner. Similarly, storage containers and bins are often used to store clothes, linen, footwear and the like, to ensure that such items are not only kept together in an ordered manner, but also organised in a manner that makes for easy access to such goods, as may be required.

Storage bins or containers may come in a variety of forms, but more recently such containers are made from a plastic material and may be formed or otherwise shaped to facilitate stacking of containers on top of each other. In this regard, such containers may have a shaped upper rim and a lower rim with an appropriate ribbing or recess formed therein to ensure that the adjacent containers mate together to provide a stable stack of containers when stacked vertically. In this regard, most conventional containers comprise a lid member that is fitted to an open surface of the container and which has sufficient resilience to support one or more vertically stacked boxes thereon.

While such containers have been shown to be useful in storing goods in a convenient and neat manner, one problem with vertically stacked containers is that in order to access the goods stored in a lower container, it is necessary to disassemble the stack of containers in order to remove the lid of a container and access the contents therein. As will be appreciated, this can be an inconvenient and time consuming process, especially if a container is not labelled and a user must search through a number of containers, each time lifting and restacking the containers.

A natural solution to this problem is to turn the containers on their sides such that the open surface of the containers is accessible by a user and to stack the containers on their side. Whilst such an arrangement would provide access into the lower containers in the stack without having to dismantle the stack, one problem with such a solution is that the side walls of the individual containers must be substantially perpendicular to the open surface to provide a level surface upon which to stack the containers.

Such a substantially rectangular or cuboid shape of container having substantially flat, perpendicular side walls does not readily lend itself to nestable stacking of empty containers for storage. Nestable stacking containers for storage is an important aspect of container design not only in use, but also in transport and supply of containers in a commercial environment. The containers must be stored when not in use and in order for the containers to take up as little space of possible, the containers are configured so as to nestably receive another container therein. Typically, in order to achieve this, the lower ends of the side walls of the containers are tapered inwards to facilitate stacking of containers when not in use. The degree of nestability of the containers can vary depending on the degree of slope or tapering of the side walls, as often just the lower regions of the boxes fit inside each other and a significant portion of the upper box extends above the lower box so that a stack of boxes stored in a nested arrangement is particularly tall and takes a considerable height. Hence the degree of tapering of the side walls of the boxes is important as the amount, or angle, of the taper determines how nestable the boxes may be.

Thus, in order to provide a set of containers that can be nestably stored when not in use, it is necessary to provide tapered walls which do not readily provide for stable stacking of boxes in a side on side manner.

Thus there is a need to provide a storage container system that provides for nestable storage of boxes in a convenient and space efficient manner, whilst still providing an ability to stack the containers on their side.

The above references to and descriptions of prior proposals or products are not intended to be, and are not to be construed as, statements or admissions of common general knowledge in the art. In particular, the above prior art discussion does not relate to what is commonly or well known by the person skilled in the art, but assists in the understanding of the inventive step of the present invention of which the identification of pertinent prior art proposals is but one part.

BRIEF SUMMARY OF THE INVENTION

Accordingly, in one aspect of the invention there is provided a stackable container comprising a body having a base, a pair of opposing side walls and a pair of opposing end walls extending from said base so as to form an opening having a rim portion extending around a periphery thereof; a lid member mountable to said body to close said opening and being configured to provide access into said body through said opening; one or more connector members provided with said body and operable between a stored state and an active state, the active state providing a means for interconnecting with an adjacent container so as to support the adjacent container in a stacked arrangement, the stacked arrangement being an arrangement whereby an adjacent container does not prohibit access into the opening of another adjacent container.

The stacked arrangement may comprise a stack of two or more containers arranged such that the side walls of adjacent containers are vertically spaced.

The lid member may be hingedly mounted to the body and be movable between a closed position that substantially closes the opening and an open position that provides uninhibited access into said opening.

The one or more connector members may be mounted on the base of the body. In another form, the one or more connector members may be mounted in a side or end wall of the body. The one or more connector members may be each mounted within a recess formed in the base of the body such that when the one or more connector members are in the stored state each connector member is substantially retained within the recess in the body. In one form, when the one or more connector members are in the active state each connector member may extend from the recess in the body to project from the body to connect with a corresponding connector member of an adjacent container.

The connector members may contain at least one male connector member and at least one female connector member with each male connector member being configured to connect with a female connector member of an adjacent container and each female connector member being configured to connect with a male connector member of an adjacent container.

Each container in the stacked arrangement may be supported at its base by the one or more connector members engaging with the one or more connector members of a lower container and is also supported at its rim portion by the rim portion of a lower container.

The one or more connector members may be removably attached to the body. In an alternative form, the one or more connector members may be securably attached to the body.

According to another aspect of the present invention, there is provided a storage container comprising a body having a base, a pair of opposing side walls and a pair of opposing end walls; a lid member mountable to said body; and one or more connector members mountable to said body to be extendable therefrom; wherein, the one or more connector members facilitate stacking of a plurality of storage containers along adjacent side walls thereof

According to yet another embodiment there is provided a storage system comprising at least one container, each container having a body comprising a base, a pair of opposing side walls and a pair of opposing end walls defining a space into which items are received, and a lid member for closing said space; and one or more connector members attachable to the or each container; wherein, each container is arranged such that is supported on one side wall and the connector members extend from the container to at least partially support another container thereon such that the containers can be stacked in a vertical manner with side walls of adjacent containers extending substantially perpendicular to the vertical stack of containers.

According to yet another embodiment there is provided a system for stacking a plurality a plurality of containers in a vertical stack, comprising a plurality of containers, each container having a base and a plurality of side walls extending from the base to define an open space into which one or more items are to be received, at least one of the side walls extends at an angle with respect to a plane orthogonal to the base, whereby each container in the vertical stack is orientated to be supported on one of the side walls thereof; and at least one connector member mounted between adjacent containers in the vertical stack, the connector member being configured to at least partially extend between the adjacent containers to compensate for angular variations between side walls of adjacent containers, such that the vertical stack of containers is maintained in a stable state.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing summary, as well as the following detailed description of preferred embodiments of the invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there is shown in the drawings embodiments which are presently preferred. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown.

FIG. 1 is a perspective view a container in accordance with an embodiment of the present invention;

FIG. 2 is a side view of the container of FIG. 1;

FIG. 3 is an end view of the container of FIG. 1;

FIG. 4 is a top perspective view of a body of the container of FIG. 1;

FIG. 5 is a top perspective view of the container of FIG. 1 with the lid member in an opened position;

FIG. 6 is a perspective view of an embodiment of a lid member of the container of FIG. 1;

FIG. 7 is a side view of the container of FIG. 1 with the lid member in an opened position;

FIG. 8 is a perspective view of the underside of the body portion of the container of FIG. 1;

FIG. 9 is an enlarged view of the recess of the body portion of FIG. 8;

FIG. 10 is an underside view of the container of FIG. 1 with the connector members in an active position;

FIG. 11 is a perspective view of a male connector member of the container of FIG. 1;

FIG. 12 is a perspective view of a female connector member of the container of FIG. 1;

FIG. 13 is an enlarged view of a female connector member mounted to an underside of the body of the container of FIG. 1;

FIG. 14 is a perspective view showing the male and female connector members in engagement in accordance with an embodiment of the present invention;

FIG. 15 is a front view of a container in accordance with the present invention in use;

FIG. 16 is a side view of the arrangement shown in FIG. 15;

FIG. 17 is a rear view of the arrangement shown in FIG. 15;

FIG. 18 is a front view of the containers of the present invention in use in a second mode of use;

FIG. 19 is a side view of the arrangement of FIG. 18;

FIG. 20 is a rear view of the arrangement of FIG. 18; and

FIG. 21 is an enlarged view showing the manner in which adjacent containers interlock in the arrangement shown in FIG. 15.

DETAILED DESCRIPTION OF THE DRAWINGS

Preferred features of the present invention will now be described with particular reference to the accompanying drawings. However, it is to be understood that the features illustrated in and described with reference to the drawings are not to be construed as limiting on the scope of the invention.

Referring to FIGS. 1-3, a container 10 in accordance with an embodiment of the present invention is shown. The container 10 generally comprises a body portion 12 having a pair of side walls 13 that extend between end walls 14. A substantially flat or level base 15 is also provided, the underside of which is configured to be supported on a support surface, such as a floor, table or other similar surface, while the upper surface of the base 15 is configured to define a floor of the container 10. In this regard, the sidewalls 13, end walls 14 and the base 15 of the container 10 define a space 16 having an open surface, through which access to the space 16 is provided.

A lid member 18 is provided to cover the open surface of the container 10 so as to enclose the space 16. The lid member 18 may take a variety of forms but generally comprises a substantially planar member having a shape configured to substantially match the open surface of the container. The lid member 18 may comprise hinge members 19 formed along on or more edges thereof to mate with corresponding hinge members provided on the upper regions of the side walls 13 or end walls 14 of the main body 12 of the container 10. The manner in which this may be achieved will be described in more detail below.

The perimeter of the lid member 18 comprises a substantially downwardly projecting flange 20 that is shaped to snugly fit over the outer, upper rim of the body portion 12 of the container 10. Such a configuration provides a secure fit of the lid member 18 to the body portion 12, which acts to substantially seal the space 16. A gripping tab 21 may be provided to extend from the flange 20 so as to be gripped by a user of the container 20 so as to provide a means for separating the lid member from the body portion 12 so as to provide access to the space 16. It will be appreciated that the planar surface 22 of the lid member 18 may be provided with ribbed members 23, as is shown which provide reinforcement or strength to the planar surface 22 such that it can bear a degree of weight, as may occur when containers are stacked on top of each other. It will also be appreciated that the lid member may be made from a substantially transparent or translucent material such that a user can at least partially look into the space 16 without removing the lid member 18, to determine the contents of the container 10. The lid member 18 is formed so as to provide stacking of multiple lid members 18, in a manner discussed in more detail below.

Referring to FIG. 2, the end walls 14 are configured to taper inwards from the upper rim thereof towards the base 15. Similarly, as is shown in FIG. 3, the side walls 13 also taper inwards from the upper rim thereof to the base 15. As will be appreciated, such an inwardly tapered arrangement provides for ease of nested stacking of the containers 10, when not in use or when stored.

As is shown in FIG. 4, when the lid member 18 is removed from the container 10, the space 16 is able to receive and store items as desired. Further, the body portions 12 of the containers 10 are able to be stacked in a nested arrangement for storage or transport. The inwardly tapered side walls 13 and end walls 14 ensure a snug nesting can be achieved with the containers 10 thereby minimising the space required to store multiple containers 10.

Referring to FIG. 5, in a preferred embodiment the lid member 18 is hingedly mounted to the main body 12 along a common edge. In the embodiment as shown, this common edge is formed along the upper rim of the end walls 14. However, it will be appreciated that the common edge may alternatively be formed along the upper rim of the side walls 13.

The lid member 18 is shown in isolation in FIG. 6. As can be clearly seen, the hinge members 19 are in the form of a plurality of fingers that extend downwardly from the flange 20. The fingers 19 are formed to have a hook or upturned portion at the ends thereof. The hook or upturned portion of the fingers 19 function to grip around a lug member 11 formed on the upper rim of the end wall 14, as shown in FIG. 7.

The underside of the base 15 is shown in more detail in FIG. 8. The underside of the base 15 comprises a substantially level or flat support surface 25. The support surface 25 extends across the undersurface of the base 15 and is substantially rectangular in configuration so as to provide a stable basis for the container 10 when positioned on a surface such as a floor or the like. At each of the corners of the support surface 25 there is provided a recess 26 that defines a space or cavity in the base 15 recessed below the support surface 25. In the embodiment as shown, the recess 26 is substantially rectangular in configuration and extends so that the length of the recess 26 extends substantially parallel with the side walls 13.

A mount 27 is provided in each recess 26 as shown in FIG. 9. The mount 27 is in the form of a raised element located in each recess 26 adjacent the end walls 14. The mount 27 extends above the surface of the recess 26 to a height that is substantially level with, or just below the support surface 25. The mount 27 has a head portion 28 formed at a periphery thereof the, purposes of which will be described in more detail below. In a preferred embodiment, the mounts 27 are formed integral with the body 12. However, as will become more apparent below, the mounts 27 may take a variety of forms and may be separately attached to the body 12, and still fall within the spirit of the present invention.

The mounts 27 each receive a connector member 29, 30, as is shown in FIG. 10, such that the connector member 29, 30 is secured in within the recesses 26. Two types of connector members are provided, a male connector member 29 (shown in FIG. 11) and a female connector member 30 (shown in FIG. 12). The male connector members 29 are mounted within the recesses formed along one side will 13, whilst the female connector members 30 are mounted within the recesses formed along the opposing side wall 13. The male connector members 29 have substantially the same length as the female connector members 30 and are mounted to the mounts 27 in substantially the same manner.

Referring to FIG. 11, the male connector member 29 comprises a main body 31 having a proximal end 35 and a distal end 36. A projection 32 is provided at the distal end 36 in the form of a substantially rigid tab member. The projection 32 has a length that projects beyond the main body 31 a length at distance of between 10-40% the length of the main body 31. In a preferred form the projection 32 has a length around 20% the length of the main body 31.

The proximal end 35 of the male connector member 29 has a hole or recess 34 formed therein. In the embodiment as shown, the hole or recess 34 is substantially circular and has a diameter substantially equivalent to the diameter of the mount 27. This enables the connector member 29 to be fitted over the mount 27 and securely retained in position thereon. The hole or recess 34 has a rim 34 a that tapers outward so as to accommodate the head portion 28 of the mount 27, thereby acting to provide a retaining force to retain the connector member in engagement with the mount 27.

Referring to FIG. 12, the female connector member 30 is shown. The female connector member 30 also comprises a main body 31 having a proximal end 35 and a distal end 36. A slot 33 is provided at the distal end 36 and has a sufficient width and depth to accommodate rigid tab member of the projection 32. In this regard, the slot 33 receives the projection 32 to facilitate engagement between a male connector member 29 of one container and a female connector member 30 of another container, as is shown in FIG. 14 and which will be described in more detail below.

The proximal end 35 of the female connector member 30 also has a hole or recess 34 formed therein. In the embodiment as shown, the hole or recess 34 is substantially circular and has a diameter substantially equivalent to the diameter of the mount 27. This enables the connector member 30 to be fitted over the mount 27 and securely retained in position thereon in the same manner as described above in relation to the male connector member 29, as is shown in FIG. 13.

The connector members 29, 30 are secured in position within the recesses 26 so as to be movable between an active position and a stored position, as represented by the arrows in FIG. 10. In the stored position, the connector members 29, 30 are substantially received within the recess 26. In the active position of the connector members 29, 30, as is shown in FIG. 10, the connector members 29, 30 project from the base 15 to extend beyond the lower region of the side walls 13. In such an active position, a projection 32 of the male connector member 29 of one container 10 is able to be received within a slot 33 of a female connector member

To move between the stored position and the active position, the connector members 29, 30 are rotated within an arc of substantially 90°. To prevent the connector members 29, 30 rotating beyond this substantially 90° arc, the proximal ends 35 are shaped to limit rotational movement. The proximal end 35 of both the male connector member 29 and the female connector member 30 has a rounded edge 35 a and a substantially right angled edge 35 b, as shown. When the connector members 29, 30 are in the stored position the rounded edge 35 a is located on an inside surface substantially in contact with the wall of the recess 26. The angled edge 35 b is thus located on an outer surface thereof. By moving the connector members 29, 30 to the active position, the angled edge 35 b moves in contact with the all of the recess, as shown in FIG. 10, thus acting to resist further rotational movement of the connector members 29, 30.

In the arrangement of the containers 10 as described above, the containers can be used in a variety of ways to store items. In this regard, the containers may be used individually, in a conventional manner, wherein the base 15 is supported on a floor surface of the like, as is shown in FIG. 5, whereby a user is able to access the storage space 16 by removing or lifting the lid member 18. It will be appreciated that a number of containers may be stacked on top of each other when used in this manner.

Another arrangement for using a container of the present invention is shown in FIGS. 15-17. In this arrangement, a single container 10 can be used such that the container is located on its side, with the side walls 13 forming the upper and lower walls of the container. As is shown more clearly in FIG. 16, in this arrangement, the container 10 is supported on a surface 5 by way of the front edge of the body 12 and the connector members 30 located at the rear of the container. By moving the female connector members 30 to the active position, the distal ends 36 thereof contact the surface 5 to function as legs at the rear of the container 10. In this regard, the length of the connector members 30 that projects beyond the base 15 of the container 10 is determined to substantially match the edge of the upper region of the body 12 to ensure that the container remains substantially level so as not to topple over in use. It will be appreciated that such an arrangement provides for the container to be used on its side despite the fact that the side walls 13 are significantly tapered, as is evident in FIG. 16.

As a variation of the arrangement shown in FIGS. 15-17, the multiple containers 10 of the present invention can be stacked on their sides to form shelving or the like, in the manner as shown in FIGS. 18-21. In the embodiment as shown, three containers 10 are stored in a stacked manner; however, it will be appreciated that any number of containers 10 may be stored in this manner and still fall within the spirit of the present invention.

As is more clearly seen in FIG. 19, the bottommost container 10 is positioned in the same manner as discussed above in relation to FIGS. 15-17 so as to be located on its side in a stable manner. The container is supported on surface 5, with the male connector members 29 moved to the active position. A second container 10 is positioned on top of the bottommost container such that the male connect members 29 of the bottommost container are received within the female connector members of the second container. The front edge of the rim of the body portion 12 of the second container is reported on the front edge of the rim of the bottommost container as shown, such that the second container is supported at a front and rear edge thereof. In the same manner, a third container 10 can be positioned on top of the second container such that the female connector members 30 of the third container receive the upwardly projecting male connector members of the second container (see FIG. 21), with the front edge of the rim of the body portion 12 of the third container resting upon the front edge of the rim of the body portion of the second container.

When stacked in the manner as shown in FIGS. 19-21, a user can readily access goods stored in any of the containers by merely opening the lip member 18. As access to the inside of the containers 10 is not impeded by the container located above, there is no need for a user to unstack a pile of containers each time they are required to search for an item. The very act of searching through the containers for a specific item is also much easier due to the side stacking arrangement. To further assist, the lid members 18 may be made from an opaque or see-through plastic material that provides visual access into the contents of the container without the need to open the lid member.

When the containers are not in use, they can be stacked in a nested arrangement due to the tapered side walls 13 and end walls 14. It will be appreciated that the degree of taper of the side walls and the end walls may vary depending upon the application of the container, and there is no need for the degree of taper to be the same for each side wall 13 and end wall 14 of a container. In order to facilitate nesting of the bodies 12, each container will need to have the same configuration.

Whilst the containers of the above embodiments have been shown with male and female connector elements that interlock with corresponding male or female connector members on a corresponding container, it will be appreciated that a variety of different types and styles of connection means may be employed to achieve this purpose. In this regard, it may be possible to incorporate cam levers and the like to act as spacers and or connecting elements between containers and still fall within the spirit of the present invention. Further to this, each of the connector members 29, 30 have been described above as being formed in or provided with the container 10. It will be appreciated that the connector members 29, 30 may be made or formed separately to the container 10 and may be sold or otherwise provided as a separate part for use with the containers. As such, the connector members may be sold loosely with the containers rather than fitted within the base of the containers, as will be appreciated by those skilled in the art.

The connector members have also been described as being mounted within a base of the container. However, it will be appreciated that the connector members may alternatively be mounted in or otherwise connectable to a side or end wall of the containers adjacent a base of the container, and still fall within the scope of the present invention.

The features and parts of the containers of the present invention are preferably made from a plastic material such as polypropylene or polyethylene by way of an injection moulding process. However, it is envisaged that other materials and processes may also be used and still fall within the spirit of the present invention.

Throughout the specification and claims the word “comprise” and its derivatives are intended to have an inclusive rather than exclusive meaning unless the contrary is expressly stated or the context requires otherwise. That is, the word “comprise” and its derivatives will be taken to indicate the inclusion of not only the listed components, steps or features that it directly references, but also other components, steps or features not specifically listed, unless the contrary is expressly stated or the context requires otherwise.

Orientational terms used in the specification and claims such as vertical, horizontal, top, bottom, upper and lower are to be interpreted as relational and are based on the premise that the component, item, article, apparatus, device or instrument will usually be considered in a particular orientation, typically with the container uppermost. It will be appreciated by those skilled in the art that many modifications and variations may be made to the methods of the invention described herein without departing from the spirit and scope of the invention. 

I claim:
 1. A container comprising: a body having a base, a pair of opposing side walls and a pair of opposing end walls extending from said base so as to form an opening having a rim portion extending around a periphery thereof; a lid member mountable to said body to close said opening and being configured to provide access into said body through said opening; one or more connector members provided with said body and operable between a stored state and an active state, wherein the active state provides a means for interconnecting with an adjacent container so as to support the adjacent container in a stacked arrangement, the stacked arrangement being an arrangement whereby an adjacent container does not prohibit access into the opening of another adjacent container.
 2. A container according to claim 1, wherein the stacked arrangement comprising a stack of two or more containers such that the side walls of adjacent containers are vertically spaced.
 3. A container according to claim 2, wherein the lid member is hingedly mounted to the body and is movable between a closed position that substantially closes the opening and an open position that provides uninhibited access into said opening.
 4. A container according to claim 1, wherein the one or more connector members are mounted on the base of said body
 5. A container according to claim 4, wherein the one or more connector members are each mounted within a recess formed in the base of the body such that when the one or more connector members are in the stored state each connector member is substantially retained within the recess in the body.
 6. A container according to claim 5, wherein when the one or more connector members are in the active state each connector member extends from the recess in the body to project from the body to connect with a corresponding connector member of an adjacent container.
 7. A container according to claim 4, wherein the connector members contain at least one male connector member and at least one female connector member with each male connector member being configured to connect with a female connector member of an adjacent container and each female connector member being configured to connect with a male connector member of an adjacent container.
 8. A container according to claim 2, wherein each container in the stacked arrangement is supported at its base by the one or more connector members engaging with the one or more connector members of a lower container and is also supported at its rim portion by the rim portion of a lower container.
 9. A container according to claim 1, wherein the one or more connector members are removably attached to the body.
 10. A container according to claim 1, wherein the one or more connector members are securably attached to the body.
 11. A storage container comprising: a body having a base, a pair of opposing side walls and a pair of opposing end walls; a lid member mountable to said body; and and one or more connector members mountable to said body to be extendable therefrom; wherein, the one or more connector members facilitate stacking of a plurality of storage containers along adjacent side walls thereof.
 12. A storage system comprising: at least one container, each container having a body comprising a base, a pair of opposing side walls and a pair of opposing end walls defining a space into which items are received, and a lid member for closing said space; and one or more connector members attachable to the or each container; wherein, each container is arranged such that is supported on one side wall and the connector members extend from the container to at least partially support another container thereon such that the containers can be stacked in a vertical manner with side walls of adjacent containers extending substantially perpendicular to the vertical stack of containers.
 13. A system for stacking a plurality of containers in a vertical stack, comprising: a plurality of containers, each container having a base and a plurality of side walls extending from the base to define an open space into which one or more items are to be received, at least one of the side walls extends at an angle with respect to a plane orthogonal to the base, whereby each container in the vertical stack is orientated to be supported on one of the side walls thereof; and at least one connector member mounted between adjacent containers in the vertical stack, the connector member being configured to at least partially extend between the adjacent containers to compensate for angular variations between side walls of adjacent containers, such that the vertical stack of containers is maintained in a stable state.
 14. A system according to claim 13, wherein the at least one connector member is mounted on an external surface of the base of each container and is configured to project therefrom to engage with a vertically adjacent container.
 15. A system according to claim 14, wherein each connector member engages with a corresponding connector member mounted on a vertically adjacent container to support the stack of containers in the stable state.
 16. A system according to claim 13, wherein each side wall of each container is angled with respect to a plane orthogonal to the base.
 17. A system according to claim 14, wherein each side wall of each container is angled with respect to a plane orthogonal to the base.
 18. A system according to claim 15, wherein each side wall of each container is angled with respect to a plane orthogonal to the base. 